EADS has used the opening day of the 2011 Paris Airshow to showcase an aircraft of the future concept which contemplates speeds beyond Mach 4, meaning it could make the run from Tokyo to London in under 2.5 hours. The ZEHST (Zero Emission Hypersonic Transport) study incorporates three different propulsion systems and could carry passengers to heights of 100,000 feet (32 km) while still meeting the projected European Commission targets for reduced noise, CO2 and NOX emissions by 2050. Blue sky indeed!